javascript - Isn't a prototype object an instance? -

I have some code that can not understand. I did not understand why the false returned.
Is not a prototype object an example?

  js> "" .__proto (new string ("")) jsa & gt; (New string ("")) example string true js & gt; ".__. Proto__ instanceof string false    
 
 
 This is basically the same.  
  string.prototype   is , according to a string, specification:  
 
 string prototype object is the string object <<>>    ]  The value of the internal property is the standard built object prototype object ().   
 But this constructor function is not an example of the  string .  
 Property constructor function of  prototype  by comparing the prototype of this example, i.e.  
  object.jetprototypeoff (string.prototype) == = String.prototype   
 Therefore, you are checking whether  string.prototype  is the  self  prototype, which is exactly  False is . Prototype of  String.prototype , as specified in the specification,  Object.prototype .  
 
 One word about the first example:  
  & gt; JS & gt; "" .__proto (new string (""))   
 You have to be careful that the console (or RELP) uses some estimates to format and present values, for example For this object, the "code" creator can read the  property, to determine what type of "value" is and according to which the output is formatted what the Chrome console is doing:  
  var str = new string ('foo'); Str instanceof string = & gt; True console Dior (str); = & Gt; String Vor obj = {}; Console.dir (obj); = & Gt; Object // good obj.constructor = string appears; = & Gt; Console.dir (obj); String // what is yaham? Obj instanceof string = & gt; False   
 It happens that every prototype object has a  constructor  property, which points back to the function, it is a prototype object, that is,  
  function fu () {} Foo.prototype.constructor === Foo; = & Gt; True Console Der (F.Portotype) = & gt; Foo   
 So if you log a prototype object, then the output can suggest that the object is an example of the function, even though it is not, only  constructor  Property